U.S. patent number 8,669,341 [Application Number 13/594,912] was granted by the patent office on 2014-03-11 for solid-state polymerization of a liquid crystalline polymer.
This patent grant is currently assigned to Ticona LLC. The grantee listed for this patent is Steven D. Gray, Kamlesh P. Nair. Invention is credited to Steven D. Gray, Kamlesh P. Nair.
United States Patent |
8,669,341 |
Nair , et al. |
March 11, 2014 |
Solid-state polymerization of a liquid crystalline polymer
Abstract
A method for forming a high molecular weight thermotropic liquid
crystalline polymer is provided. The method includes melt
polymerizing two or more monomers in the presence of a unique
aromatic amide oligomer to form a prepolymer, and then solid-state
polymerizing the prepolymer to achieve a target molecular weight.
The present inventors have discovered that a unique aromatic amide
oligomer can be employed to help increase the "low shear" complex
viscosity of the resulting solid-state polymerized composition.
This allows for the attainment of higher than conventional "low
shear" complex viscosity values and/or a substantial reduction in
the solid-state polymerization time needed to achieve a target
complex viscosity. In addition, the oligomeric flow aid can also
accelerate the extent to which the "high shear" melt viscosity is
increased during solid-state polymerization, which may also
contribute to a substantial reduction in the solid-state
polymerization time needed to achieve a certain molecular
weight.
Inventors: |
Nair; Kamlesh P. (Florence,
KY), Gray; Steven D. (Mequon, WI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Nair; Kamlesh P.
Gray; Steven D. |
Florence
Mequon |
KY
WI |
US
US |
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Assignee: |
Ticona LLC (Florence,
KY)
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Family
ID: |
46759122 |
Appl.
No.: |
13/594,912 |
Filed: |
August 27, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20130053533 A1 |
Feb 28, 2013 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61528424 |
Aug 29, 2011 |
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61664891 |
Jun 27, 2012 |
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Current U.S.
Class: |
528/193;
528/190 |
Current CPC
Class: |
C09K
19/3086 (20130101); C09K 19/3444 (20130101); C09K
19/22 (20130101); C09K 19/322 (20130101); C09K
19/48 (20130101); C09K 2019/0481 (20130101); C08K
5/20 (20130101) |
Current International
Class: |
C08G
63/02 (20060101); C08G 64/00 (20060101) |
Field of
Search: |
;528/190,193 |
References Cited
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WO |
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WO 2007/038373 |
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Apr 2007 |
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WO |
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Primary Examiner: Boykin; Terressa
Attorney, Agent or Firm: Dority & Manning, P.A.
Parent Case Text
RELATED APPLICATIONS
The present application claims priority to U.S. provisional
application Ser. Nos. 61/528,424, filed on Aug. 29, 2011, and
61/664,891, filed on Jun. 27, 2012, which are incorporated herein
in their entirety by reference thereto.
Claims
What is claimed is:
1. A method for forming liquid crystalline polymer, the method
comprising: melt polymerizing two or more monomers in the presence
of an aromatic amide oligomer to form a prepolymer, wherein the
oligomer has a molecular weight of from about 325 to about 5,000
grams per mole and has the following general formula (I):
##STR00026## wherein, ring B is a 6-membered aromatic ring wherein
1 to 3 ring carbon atoms are optionally replaced by nitrogen or
oxygen, wherein each nitrogen is optionally oxidized, and wherein
ring B may be optionally fused or linked to a 5- or 6-membered
aryl, heteroaryl, cycloalkyl, or heterocyclyl; R.sub.5 is halo,
haloalkyl, alkyl, alkenyl, aryl, heteroaryl, cycloalkyl, or
heterocyclyl; m is from 0 to 4; X.sub.1 and X.sub.2 are
independently C(O)HN or NHC(O); R.sub.1 and R.sub.2 are
independently selected from aryl, heteroaryl, cycloalkyl, and
heterocyclyl; and thereafter, solid-state polymerizing the
prepolymer to form the liquid crystalline polymer.
2. The method of claim 1, wherein the liquid crystal polymer is
wholly aromatic.
3. The method of claim 1, wherein the ratio of the melt viscosity
of the liquid crystalline polymer to the melt viscosity of the
prepolymer is from about 3 to about 20, as determined by a
capillary rheometer at a shear rate of 1000 seconds.sup.-1 and
temperature of 375.degree. C.
4. The method of claim 3, wherein the liquid crystalline polymer
has a melt viscosity of from about 100 to about 2,000 Pa-s and the
prepolymer has a melt viscosity of from about 10 to about 250 Pa-s,
as determined by a capillary rheometer at a shear rate of 1000
seconds.sup.-1 and temperature of 375.degree. C.
5. The method of claim 1, wherein the polymer has a complex
viscosity of about 100 kPa-s or more, determined by a parallel
plate rheometer at an angular frequency of 0.15 radians per second,
temperature of 375.degree. C., and constant strain amplitude of
1%.
6. The method of claim 1, wherein ring B is phenyl.
7. The method of claim 1, wherein ring B is naphthyl.
8. The method of claim 1, wherein the aromatic amide oligomer has
the following general formula (III): ##STR00027## wherein, X.sub.1
and X.sub.2 are independently C(O)HN or NHC(O); R.sub.5, R.sub.6,
and R.sub.7 are independently selected from halo, haloalkyl, alkyl,
alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, and heterocyclyl; m
is from 0 to 4; and n and p are independently from 0 to 5.
9. The method of claim 8, wherein m is 0, n is from 1 to 5, and p
is from 1 to 5.
10. The method of claim 9, wherein R.sub.6, R.sub.7, or both are
unsubstituted aryl or aryl substituted with an amide group having
the structure: --C(O)R.sub.12N-- or --NR.sub.13C(O)--, wherein
R.sub.12 and R.sub.13 are independently selected from hydrogen,
alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, and
heterocyclyl.
11. The method of claim 9, wherein R.sub.6 and R.sub.7 are phenyl
substituted with --C(O)HN-- or --NHC(O)--.
12. The method of claim 1, wherein the aromatic amide oligomer has
the following general formula (IV): ##STR00028## wherein, X.sub.1,
X.sub.2, and X.sub.3 are independently C(O)HN or NHC(O); R.sub.5,
R.sub.7, R.sub.8, and R.sub.9 are independently selected from halo,
haloalkyl, alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl,
and heterocyclyl; m is from 0 to 3; and p, q, and r are
independently from 0 to 5.
13. The method of claim 12, wherein R.sub.7, R.sub.8, and/or
R.sub.9 are unsubstituted aryl or aryl substituted with an amide
group having the structure: --C(O)R.sub.12N-- or --NR.sub.13C(O)--,
wherein R.sub.12 and R.sub.13 are independently selected from
hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl,
and heterocyclyl.
14. The method of claim 13, wherein R.sub.7, R.sub.8, and/or
R.sub.9 are phenyl substituted with --C(O)HN-- or --NHC(O)--.
15. The method of claim 1, wherein the oligomer is selected from
the group consisting of the following compounds and combinations
thereof: TABLE-US-00004 Structure Name ##STR00029## N1,N4-bis(4-
benzamidophenyl)terephthalamide ##STR00030## N4-phenyl-N1-[4-[[4-
(phenylcarbamoyl)ben- zoyl]amino]phenyl]terephthalamide
##STR00031## N4-phenyl-N1-[3-[[4- (phenylcarbamoyl)ben-
zoyl]amino]phenyl]terephthalamide ##STR00032## N1,N3-bis(4-
benzamidophenyl)benzene-1,3- dicarboxamide ##STR00033##
N3-phenyl-N1-[3-[[3- (phenylcarbamoyl)ben-
zoyl]amino]phenyl]benzene- 1,3-dicarboxamide ##STR00034##
N1,N3-bis(3- benzamidophenyl)benzene-1,3- dicarboxamide
##STR00035## N1,N3-bis(4-phenylphenyl)benzene- 1,3-dicarboxamide
##STR00036## N1,N3,N5-triphenylbenzene-1,3,5- tricarboxamide
##STR00037## N-(4,6-dibenzamido-1,3,5-triazin-2- yl)benzamide
##STR00038## N1,N3,N5-tris(4- benzamidophenyl)benzene-1,3,5-
tricarboxamide ##STR00039## N1,N3,N5-tris(3-
benzamidophenyl)benzene-1,3,5- tricarboxamide
16. The method of claim 1, wherein the oligomer contains from 3 to
8 amide functional groups per molecule.
17. The method of claim 1, wherein the oligomer has a molecular
weight of from about 400 to about 1,500 grams per mole.
18. The method of claim 1, wherein the monomers are selected from
the group consisting of aromatic hydroxycarboxylic acids, aromatic
dicarboxylic acids, aromatic diols, aromatic amines, aromatic
diamines, and combinations thereof.
19. The method of claim 1, wherein the melt polymerizing of the
monomers comprises heating a reaction mixture comprising the
monomers and the oligomer within a reactor vessel to initiate a
melt polycondensation reaction.
20. The method of claim 19, wherein aromatic amide oligomers are
employed in an amount of from about 0.1 to about 5 parts by weight
relative to 100 parts by weight of the reaction mixture.
21. The method of claim 1, wherein the solid-state polymerizing of
the prepolymer comprises heating the prepolymer in the presence of
a gas to initiate chain extension of the prepolymer.
22. A thermoformed article that comprises a liquid crystalline
polymer formed according to the method of claim 1.
23. A sheet for use in thermoforming an article, the sheet
comprising a thermotropic liquid crystalline polymer composition
that includes a liquid crystalline polymer melt polymerized in the
presence of an aromatic amide oligomer, wherein the composition has
a melt viscosity of from about 150 to about 1,600 Pa-s as
determined by a capillary rheometer at a shear rate of 1000
seconds.sup.-1 and a temperature of 375.degree. C. and a complex
viscosity of about 200 kPa-s or more as determined by a parallel
plate rheometer at an angular frequency of 0.15 radians per second,
temperature of 375.degree. C., and constant strain amplitude of
1%.
24. The sheet of claim 23, wherein the polymer has a melt viscosity
of from about 200 to about 900 Pa-s as determined at a shear rate
of 1000 seconds-1 and a temperature of 375.degree. C. and a complex
viscosity of from about 300 to about 2,000 kPa-s as determined at
an angular frequency of 0.15 radians per second, temperature of
375.degree. C., and constant strain amplitude of 1%.
25. The sheet of claim 23, wherein the polymer has a number average
molecular weight of about 2,000 grams per mole or more.
26. The sheet of claim 23, wherein the polymer has a melting
temperature of from about 270.degree. C. to about 380.degree.
C.
27. The sheet of claim 23, wherein the liquid crystalline polymer
is wholly aromatic.
Description
BACKGROUND OF THE INVENTION
Thermotropic liquid crystalline polymers are classified as "rigid
rod" polymers as their molecular structure is typically composed of
aromatic units linked by functional groups such as esters and/or
amides. The rigid, rod-like structure allows the polymers to
exhibit liquid crystalline behavior in their molten state
(thermotropic nematic state). High molecular weight liquid
crystalline polymers have interesting properties, such as a high
melt viscosity, high thermal stability, and enhanced flow along
with good mechanical properties. These properties make them
attractive in diverse fields such as sheet extrusion, thermoforming
processes, etc. For these types of applications, it is advantageous
to have a material with high melt strength or enhanced "low shear"
viscosity. Due to the high melting points of these polymers (e.g.,
above about 350.degree. C.), however, the melt viscosity required
for these applications is very high and must be obtained by
solid-state polymerization. In a solid-state polymerization
process, a low molecular weight, melt polymerized prepolymer is
heated below its melting point (and above its glass transition
temperature) so that chain-extension can take place and result in a
higher molecular weight resulting in increased melt viscosity of
the polymer. However this process can be quite time-consuming and
thus can significantly add more cost to the product.
As such, a need currently exists for a technique of accelerating
the build-up of viscosity during solid-state polymerization, which
can in turn decrease the time needed to achieve the required melt
viscosity.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention, a
method for forming a liquid crystalline polymer is disclosed. The
method comprises melt polymerizing two or more monomers in the
presence of an aromatic amide oligomer to form a prepolymer and
thereafter, solid-state polymerizing the prepolymer to form the
liquid crystalline polymer. The oligomer has a molecular weight of
from about 325 to about 5,000 grams per mole and has the following
general formula (I):
##STR00001## wherein,
ring B is a 6-membered aromatic ring wherein 1 to 3 ring carbon
atoms are optionally replaced by nitrogen or oxygen, wherein each
nitrogen is optionally oxidized, and wherein ring B may be
optionally fused or linked to a 5- or 6-membered aryl, heteroaryl,
cycloalkyl, or heterocyclyl;
R.sub.5 is halo, haloalkyl, alkyl, alkenyl, aryl, heteroaryl,
cycloalkyl, or heterocyclyl;
m is from 0 to 4;
X.sub.1 and X.sub.2 are independently C(O)HN or NHC(O); and
R.sub.1 and R.sub.2 are independently selected from aryl,
heteroaryl, cycloalkyl, and heterocyclyl.
In accordance with another embodiment of the present invention, a
sheet for use in thermforming an article is disclosed. The sheet
comprises a thermotropic liquid crystalline polymer composition
that comprises a liquid crystalline polymer melt polymerized in the
presence of an aromatic amide oligomer. The composition has a melt
viscosity of from about 150 to about 1,500 Pa-s as determined at a
shear rate of 1000 seconds.sup.-1 and a temperature of 370.degree.
C. and a complex viscosity of about 200 kPa-s or more as determined
at an angular frequency of 0.15 radians per second, temperature of
370.degree. C., and constant strain amplitude of 1%.
Other features and aspects of the present invention are set forth
in greater detail below.
BRIEF DESCRIPTION OF THE FIGURES
A full and enabling disclosure of the present invention, including
the best mode thereof to one skilled in the art, is set forth more
particularly in the remainder of the specification, including
reference to the accompanying figures, in which:
FIG. 1 is the Proton NMR characterization for
N1,N3-bis(4-benzamidophenyl)benzene-1,3-dicarboxamide (Compound
C2);
FIG. 2 is the Proton NMR characterization for
N1,N3-bis(3-benzamidophenyl)benzene-1,3-dicarboxamide (Compound
D2);
FIG. 3 is the Proton NMR characterization for
N1,N3,N5-triphenylbenzene-1,3,5-tricarboxamide (Compound F);
FIG. 4 is the Proton NMR characterization for
N1,N3,N5-tris(4-benzamidophenyl)benzene-1,3,5-tricarboxamide
(Compound H); and
FIG. 5 is a graph showing complex viscosity (Pa*s) versus frequency
(rad/s) for the solid-state polymerized samples of Examples
1-4.
DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS
Definitions
It is to be understood that the terminology used herein is for the
purpose of describing particular embodiments only and is not
intended to limit the scope of the present invention.
"Alkyl" refers to monovalent saturated aliphatic hydrocarbyl groups
having from 1 to 10 carbon atoms and, in some embodiments, from 1
to 6 carbon atoms. "C.sub.x-yalkyl" refers to alkyl groups having
from x to y carbon atoms. This term includes, by way of example,
linear and branched hydrocarbyl groups such as methyl (CH.sub.3),
ethyl (CH.sub.3CH.sub.2), n-propyl (CH.sub.3CH.sub.2CH.sub.2),
isopropyl ((CH.sub.3).sub.2CH), n-butyl
(CH.sub.3CH.sub.2CH.sub.2CH.sub.2), isobutyl
((CH.sub.3).sub.2CHCH.sub.2), sec-butyl
((CH.sub.3)(CH.sub.3CH.sub.2)CH), t-butyl ((CH.sub.3).sub.3C),
n-pentyl (CH.sub.3CH.sub.2CH.sub.2CH.sub.2CH.sub.2), and neopentyl
((CH.sub.3).sub.3CCH.sub.2).
"Alkenyl" refers to a linear or branched hydrocarbyl group having
from 2 to 10 carbon atoms and in some embodiments from 2 to 6
carbon atoms or 2 to 4 carbon atoms and having at least 1 site of
vinyl unsaturation (>C.dbd.C<). For example,
(C.sub.x-C.sub.y)alkenyl refers to alkenyl groups having from x to
y carbon atoms and is meant to include for example, ethenyl,
propenyl, 1,3-butadienyl, and so forth.
"Alkynyl" refers to refers to a linear or branched monovalent
hydrocarbon radical containing at least one triple bond. The term
"alkynyl" may also include those hydrocarbyl groups having other
types of bonds, such as a double bond and a triple bond.
"Aryl" refers to an aromatic group of from 3 to 14 carbon atoms and
no ring heteroatoms and having a single ring (e.g., phenyl) or
multiple condensed (fused) rings (e.g., naphthyl or anthryl). For
multiple ring systems, including fused, bridged, and Spiro ring
systems having aromatic and non-aromatic rings that have no ring
heteroatoms, the term "Aryl" applies when the point of attachment
is at an aromatic carbon atom (e.g., 5,6,7,8
tetrahydronaphthalene-2-yl is an aryl group as its point of
attachment is at the 2-position of the aromatic phenyl ring).
"Cycloalkyl" refers to a saturated or partially saturated cyclic
group of from 3 to 14 carbon atoms and no ring heteroatoms and
having a single ring or multiple rings including fused, bridged,
and spiro ring systems. For multiple ring systems having aromatic
and non-aromatic rings that have no ring heteroatoms, the term
"cycloalkyl" applies when the point of attachment is at a
non-aromatic carbon atom (e.g.
5,6,7,8,-tetrahydronaphthalene-5-yl). The term "cycloalkyl"
includes cycloalkenyl groups, such as adamantyl, cyclopropyl,
cyclobutyl, cyclopentyl, cyclooctyl, and cyclohexenyl. The term
"cycloalkenyl" is sometimes employed to refer to a partially
saturated cycloalkyl ring having at least one site of
>C.dbd.C<ring unsaturation.
"Halo" or "halogen" refers to fluoro, chloro, bromo, and iodo.
"Haloalkyl" refers to substitution of alkyl groups with 1 to 5 or
in some embodiments 1 to 3 halo groups.
"Heteroaryl" refers to an aromatic group of from 1 to 14 carbon
atoms and 1 to 6 heteroatoms selected from oxygen, nitrogen, and
sulfur and includes single ring (e.g. imidazolyl) and multiple ring
systems (e.g. benzimidazol-2-yl and benzimidazol-6-yl). For
multiple ring systems, including fused, bridged, and spiro ring
systems having aromatic and non-aromatic rings, the term
"heteroaryl" applies if there is at least one ring heteroatom and
the point of attachment is at an atom of an aromatic ring (e.g.
1,2,3,4-tetrahydroquinolin-6-yl and
5,6,7,8-tetrahydroquinolin-3-yl). In some embodiments, the nitrogen
and/or the sulfur ring atom(s) of the heteroaryl group are
optionally oxidized to provide for the N oxide (N.fwdarw.O),
sulfinyl, or sulfonyl moieties. Examples of heteroaryl groups
include, but are not limited to, pyridyl, furanyl, thienyl,
thiazolyl, isothiazolyl, triazolyl, imidazolyl, imidazolinyl,
isoxazolyl, pyrrolyl, pyrazolyl, pyridazinyl, pyrimidinyl, purinyl,
phthalazyl, naphthylpryidyl, benzofuranyl, tetrahydrobenzofuranyl,
isobenzofuranyl, benzothiazolyl, benzoisothiazolyl, benzotriazolyl,
indolyl, isoindolyl, indolizinyl, dihydroindolyl, indazolyl,
indolinyl, benzoxazolyl, quinolyl, isoquinolyl, quinolizyl,
quianazolyl, quinoxalyl, tetrahydroquinolinyl, isoquinolyl,
quinazolinonyl, benzimidazolyl, benzisoxazolyl, benzothienyl,
benzopyridazinyl, pteridinyl, carbazolyl, carbolinyl,
phenanthridinyl, acridinyl, phenanthrolinyl, phenazinyl,
phenoxazinyl, phenothiazinyl, and phthalimidyl.
"Heterocyclic" or "heterocycle" or "heterocycloalkyl" or
"heterocyclyl" refers to a saturated or partially saturated cyclic
group having from 1 to 14 carbon atoms and from 1 to 6 heteroatoms
selected from nitrogen, sulfur, or oxygen and includes single ring
and multiple ring systems including fused, bridged, and spiro ring
systems. For multiple ring systems having aromatic and/or
non-aromatic rings, the terms "heterocyclic", "heterocycle",
"heterocycloalkyl", or "heterocyclyl" apply when there is at least
one ring heteroatom and the point of attachment is at an atom of a
non-aromatic ring (e.g. decahydroquinolin-6-yl). In some
embodiments, the nitrogen and/or sulfur atom(s) of the heterocyclic
group are optionally oxidized to provide for the N oxide, sulfinyl,
sulfonyl moieties. Examples of heterocyclyl groups include, but are
not limited to, azetidinyl, tetrahydropyranyl, piperidinyl,
N-methylpiperidin-3-yl, piperazinyl, N-methylpyrrolidin-3-yl,
3-pyrrolidinyl, 2-pyrrolidon-1-yl, morpholinyl, thiomorpholinyl,
imidazolidinyl, and pyrrolidinyl.
It should be understood that the aforementioned definitions
encompass unsubstituted groups, as well as groups substituted with
one or more other functional groups as is known in the art. For
example, an aryl, heteroaryl, cycloalkyl, or heterocyclyl group may
be substituted with from 1 to 8, in some embodiments from 1 to 5,
in some embodiments from 1 to 3, and in some embodiments, from 1 to
2 substituents selected from alkyl, alkenyl, alkynyl, alkoxy, acyl,
acylamino, acyloxy, amino, quaternary amino, amide, imino, amidino,
aminocarbonylamino, amidinocarbonylamino, aminothiocarbonyl,
aminocarbonylamino, aminothiocarbonylamino, aminocarbonyloxy,
aminosulfonyl, aminosulfonyloxy, aminosulfonylamino, aryl, aryloxy,
arylthio, azido, carboxyl, carboxyl ester, (carboxyl ester)amino,
(carboxyl ester)oxy, cyano, cycloalkyl, cycloalkyloxy,
cycloalkylthio, guanidino, halo, haloalkyl, haloalkoxy, hydroxy,
hydroxyamino, alkoxyamino, hydrazino, heteroaryl, heteroaryloxy,
heteroarylthio, heterocyclyl, heterocyclyloxy, heterocyclylthio,
nitro, oxo, thione, phosphate, phosphonate, phosphinate,
phosphonamidate, phosphorodiamidate, phosphoramidate monoester,
cyclic phosphoramidate, cyclic phosphorodiamidate, phosphoramidate
diester, sulfate, sulfonate, sulfonyl, substituted sulfonyl,
sulfonyloxy, thioacyl, thiocyanate, thiol, alkylthio, etc., as well
as combinations of such substituents.
"Liquid crystalline polymer" or "liquid crystal polymer" refers to
a polymer that can possess a rod-like structure that allows it to
exhibit liquid crystalline behavior in its molten state (e.g.,
thermotropic nematic state). The polymer may contain aromatic units
(e.g., aromatic polyesters, aromatic polyesteramides, etc.) so that
it is wholly aromatic (e.g., containing only aromatic units) or
partially aromatic (e.g., containing aromatic units and other
units, such as cycloaliphatic units). The polymer may also be fully
crystalline or semi-crystalline in nature.
DETAILED DESCRIPTION
It is to be understood by one of ordinary skill in the art that the
present discussion is a description of exemplary embodiments only,
and is not intended as limiting the broader aspects of the present
invention.
Generally speaking, the present invention is directed to a method
for forming a high molecular weight thermotropic liquid crystalline
polymer. The method includes melt polymerizing two or more monomers
to form a prepolymer, and then solid-state polymerizing the
prepolymer to achieve a target molecular weight. The present
inventors have discovered that a unique aromatic amide oligomer can
be employed to help increase the "low shear" complex viscosity of
the resulting solid-state polymerized composition. This allows for
the attainment of higher than conventional "low shear" complex
viscosity values and/or a substantial reduction in the solid-state
polymerization time needed to achieve a target complex viscosity.
For instance, the polymer composition may have a "low shear"
complex viscosity of about 100 kilopascal-seconds ("kPa-s") or
more, in some embodiments about 200 kPa-s or more, in some
embodiments from about 300 kPa-s to about 2,000 kPa-s, and in some
embodiments, from about 500 kPa-s to about 1,500 kPa-s. The low
shear viscosity may be determined by a parallel plate rheometer at
an angular frequency of 0.15 radians per second, a temperature of
375.degree. C., and at a constant strain amplitude of 1%.
In certain embodiments, the oligomeric flow aid may also accelerate
the extent to which the "high shear" melt viscosity is increased
during solid-state polymerization, which can correlate to the rate
at which chain extension of the prepolymer occurs. This increased
rate of chain extension may also contribute to a substantial
reduction in the solid-state polymerization time needed to achieve
a certain molecular weight. In this regard, the ratio of the "high
shear" melt viscosity of the solid-state polymerized composition to
the "high shear" melt viscosity of the melt-polymerized prepolymer
is typically from about 3 to about 20, in some embodiments from
about 4 to about 15, and in some embodiments, from about 5 to about
10. For example, the solid-state polymerized composition may have a
melt viscosity (at a temperature of 375.degree. C. and shear rate
of 1000 seconds.sup.-1) of from about 100 to about 2,000 Pa-s, in
some embodiments from about 150 to about 1,500 Pa-s, and in some
embodiments, from about 200 to about 900 Pa-s, and the
melt-polymerized prepolymer may have a melt viscosity (at a
temperature of 375.degree. C. and shear rate of 1000
seconds.sup.-1) of from about 10 to about 250 Pa-s, in some
embodiments from about 15 to about 200 Pa-s, and in some
embodiments, from about 20 to about 150 Pa-s.
One benefit of the aromatic amide flow aid is that it is not easily
volatized or decomposed, which allows the additive to be processed
at relatively high temperatures during the polymerization reaction.
Without intending to be limited by theory, it is believed that
active hydrogen atoms of the amide functional groups are capable of
forming a hydrogen bond with the backbone of liquid crystalline
polyesters or polyesteramides. Such hydrogen bonding strengthens
the attachment of the oligomer to the liquid crystalline polymer
matrix and thus minimizes the likelihood that it becomes
volatilized during formation. In this regard, the oligomer
generally possesses a high amide functionality so it is capable of
undergoing a sufficient degree of hydrogen bonding with the liquid
crystalline polymer. The degree of amide functionality for a given
molecule may be characterized by its "amide equivalent weight",
which reflects the amount of a compound that contains one molecule
of an amide functional group and may be calculated by dividing the
molecular weight of the compound by the number of amide groups in
the molecule. For example, the aromatic amide oligomer may contain
from 2 to 15, in some embodiments from 3 to 12, and in some
embodiments, from 3 to 8 amide functional groups per molecule. The
amide equivalent weight may likewise be from about 10 to about
1,000 grams per mole or less, in some embodiments from about 50 to
about 500 grams per mole, and in some embodiments, from about 100
to about 300 grams per mole. The total weight of the oligomer is
also high enough so that it can effectively increase the low shear
viscosity of the polymer, yet not so high that polymerization is
substantially inhibited. In this regard, the oligomer typically has
a molecular weight of from about 325 to about 5,000 grams per mole,
in some embodiments from about 350 to about 3,000 grams per mole,
in some embodiments from about 375 to about 2,500 grams per mole,
and in some embodiments, from about 400 to about 1,500 grams per
mole.
While providing the benefits noted above, the aromatic amide
oligomer does not generally form covalent bonds with the polymer
backbone of the liquid crystalline polymer to any appreciable
extent so that the mechanical properties of the polymer are not
adversely impacted. To help better minimize reactivity, the
oligomer typically contains a core formed from one or more aromatic
rings (including heteroaromatic). The oligomer may also contain
terminal groups formed from one or more aromatic rings and/or
cycloalkyl groups. Such an "aromatic" oligomer thus possesses
little, if any, reactivity with the base liquid crystalline
polymer. For example, one embodiment of such an aromatic amide
oligomer is provided below in Formula (I):
##STR00002## wherein,
ring B is a 6-membered aromatic ring wherein 1 to 3 ring carbon
atoms are optionally replaced by nitrogen or oxygen, wherein each
nitrogen is optionally oxidized, and wherein ring B may be
optionally fused or linked to a 5- or 6-membered aryl, heteroaryl,
cycloalkyl, or heterocyclyl;
R.sub.5 is halo, haloalkyl, alkyl, alkenyl, aryl, heteroaryl,
cycloalkyl, or heterocyclyl;
m is from 0 to 4;
X.sub.1 and X.sub.2 are independently C(O)HN or NHC(O); and
R.sub.1 and R.sub.2 are independently selected from aryl,
heteroaryl, cycloalkyl, and heterocyclyl.
In certain embodiments, Ring B in Formula (I) above may be selected
from the following:
##STR00003## wherein,
m is 0, 1, 2, 3, or 4, in some embodiments m is 0, 1, or 2, in some
embodiments m is 0 or 1, and in some embodiments, m is 0; and
R.sub.5 is halo, haloalkyl, alkyl, alkenyl, aryl, heteroaryl,
cycloalkyl, or heterocyclyl. Ring B may be phenyl.
In certain embodiments, the oligomer is a di-functional compound in
that Ring B is directly bonded to only two (2) amide groups (e.g.,
C(O)HN or NHC(O)). In such embodiments, m in Formula (I) may be 0.
Of course, in certain embodiments, Ring B may also be directly
bonded to three (3) or more amide groups. For example, one
embodiment of such a compound is provided by general formula
(II):
##STR00004## wherein,
ring B, R.sub.5, X.sub.1, X.sub.2, R.sub.1, and R.sub.2 are as
defined above;
m is from 0 to 3;
X.sub.3 is C(O)HN or NHC(O); and
R.sub.3 is selected from aryl, heteroaryl, cycloalkyl, and
heterocyclyl.
Another embodiment of such a compound is provided by general
formula (III):
##STR00005## wherein,
ring B, R.sub.5, X.sub.1, X.sub.2, X.sub.3, R.sub.1, R.sub.2, and
R.sub.3 are as defined above;
X.sub.4 is C(O)HN or NHC(O); and
R.sub.4 is selected from aryl, heteroaryl, cycloalkyl, and
heterocyclyl.
In some embodiments, R.sub.1, R.sub.2, R.sub.3, and/or R.sub.4 in
the structures noted above may be selected from the following:
##STR00006## wherein,
n is 0, 1, 2, 3, 4, or 5, in some embodiments n is 0, 1, or 2, and
in some embodiments, n is 0 or 1; and
R.sub.6 is halo, haloalkyl, alkyl, alkenyl, aryl, heteroaryl,
cycloalkyl, or heterocyclyl.
In one embodiment, the aromatic amide oligomer has the following
general formula (IV):
##STR00007## wherein,
X.sub.1 and X.sub.2 are independently C(O)HN or NHC(O);
R.sub.5, R.sub.7, and R.sub.8 are independently selected from halo,
haloalkyl, alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl,
and heterocyclyl;
m is from 0 to 4; and
p and q are independently from 0 to 5.
For example, in certain embodiments, m, p, and q in Formula (IV)
may be equal to 0 so that the core and terminal groups are
unsubstituted. In other embodiments, m may be 0 and p and q may be
from 1 to 5. In such embodiments, for example, R.sub.7 and/or
R.sub.8 may be halo (e.g., fluorine). In other embodiments, R.sub.7
and/or R.sub.8 may be aryl (e.g., phenyl), cycloalkyl (e.g.,
cyclohexyl), or aryl and/or cycloalkyl substituted with an amide
group having the structure: --C(O)R.sub.12N-- or --NR.sub.13C(O)--,
wherein R.sub.12 and R.sub.13 are independently selected from
hydrogen, alkyl, alkenyl, aryl, heteroaryl, cycloalkyl, and
heterocyclyl. In one particular embodiment, for example, R.sub.7
and/or R.sub.8 are phenyl substituted with --C(O)HN-- or
--NHC(O)--. In yet other embodiments, R.sub.7 and/or R.sub.8 may be
heteroaryl (e.g., pyridinyl).
In yet another embodiment, the aromatic amide oligomer has the
following general formula (V):
##STR00008## wherein,
X.sub.1, X.sub.2, and X.sub.3 are independently C(O)HN or
NHC(O);
R.sub.5, R.sub.7, R.sub.8, and R.sub.9 are independently selected
from halo, haloalkyl, alkyl, alkenyl, alkynyl, aryl, heteroaryl,
cycloalkyl, and heterocyclyl;
m is from 0 to 3; and
p, q, and r are independently from 0 to 5.
For example, in certain embodiments, m, p, q, and r in Formula (V)
may be equal to 0 so that the core and terminal aromatic groups are
unsubstituted. In other embodiments, m may be 0 and p, q, and r may
be from 1 to 5. In such embodiments, for example, R.sub.7, R.sub.8,
and/or R.sub.9 may be halo (e.g., fluorine). In other embodiments,
R.sub.7, R.sub.8, and/or R.sub.9 may be aryl (e.g., phenyl),
cycloalkyl (e.g., cyclohexyl), or aryl and/or cycloalkyl
substituted with an amide group having the structure:
--C(O)R.sub.12N-- or --NR.sub.13C(O)--, wherein R.sub.12 and
R.sub.13 are independently selected from hydrogen, alkyl, alkenyl,
alkynyl, aryl, heteroaryl, cycloalkyl, and heterocyclyl. In one
particular embodiment, for example, R.sub.7, R.sub.8, and/or
R.sub.9 are phenyl substituted with --C(O)HN-- or --NHC(O)--. In
yet other embodiments, R.sub.7, R.sub.8, and/or R.sub.9 may be
heteroaryl (e.g., pyridinyl).
Specific embodiments of the aromatic amide oligomer of the present
invention are also set forth in the table below:
TABLE-US-00001 Cmpd MW # Structure Name (g/mol) A ##STR00009##
N1,N4-bis(4- benzamidophen- yl)terephthalamide 554.6 B ##STR00010##
N4-phenyl-N1-[4- [[4-(phenyl- carbamoyl)ben- zoyl]amino]phen-
yl]terephthalamide 554.6 C1 ##STR00011## N4-phenyl-N1-[3-
[[4-(phenyl- carbamoyl)ben- zoyl]amino]phen- yl]terephthalamide
554.6 C2 ##STR00012## N1,N3-bis(4- benzamido- phenyl)benzene-1,3-
dicarboxamide 554.6 D1 ##STR00013## N3-phenyl-N1-[3- [[3-(phenyl-
carbamoyl)ben- zoyl]amino]phen- yl]benzene-1,3- dicarboxamide 554.6
D2 ##STR00014## N1,N3-bis(3- benzamidophen- yl)benzene-1,3-
dicarboxamide 554.6 E ##STR00015## N1,N3-bis(4- phenylphen-
yl)benzene-1,3- dicarboxamide 468.5 F ##STR00016## N1,N3,N5-
triphenylbenzene- 1,3,5-tricarboxamide 435.5 G ##STR00017##
N-(4,6-dibenzamido- 1,3,5-triazin-2- yl)benzamide 438.4 H
##STR00018## N1,N3,N5-tris(4- benzamidophen- yl)benzene-1,3,5-
tricarboxamide 792.8 I ##STR00019## N1,N3,N5-tris(3- benzamidophen-
yl)benzene-1,3,5- tricarboxamide 792.8
The precursor monomers employed during melt polymerization of the
liquid crystalline polymer may generally vary as is known in the
art. For example, suitable thermotropic liquid crystalline polymers
may include instance, aromatic polyesters, aromatic
poly(esteramides), aromatic poly(estercarbonates), aromatic
polyamides, etc., and may likewise contain repeating units formed
from one or more aromatic or aliphatic hydroxycarboxylic acids,
aromatic or aliphatic dicarboxylic acids, aromatic or aliphatic
diols, aromatic or aliphatic aminocarboxylic acids, aromatic or
aliphatic amines, aromatic or aliphatic diamines, etc., as well as
combinations thereof.
Aromatic polyesters, for instance, may be obtained by polymerizing
(1) two or more aromatic hydroxycarboxylic acids; (2) at least one
aromatic hydroxycarboxylic acid, at least one aromatic dicarboxylic
acid, and at least one aromatic diol; and/or (3) at least one
aromatic dicarboxylic acid and at least one aromatic diol. Examples
of suitable aromatic hydroxycarboxylic acids include,
4-hydroxybenzoic acid; 4-hydroxy-4'-biphenylcarboxylic acid;
2-hydroxy-6-naphthoic acid; 2-hydroxy-5-naphthoic acid;
3-hydroxy-2-naphthoic acid; 2-hydroxy-3-naphthoic acid;
4'-hydroxyphenyl-4-benzoic acid; 3'-hydroxyphenyl-4-benzoic acid;
4'-hydroxyphenyl-3-benzoic acid, etc., as well as alkyl, alkoxy,
aryl and halogen substituents thereof. Examples of suitable
aromatic dicarboxylic acids include terephthalic acid; isophthalic
acid; 2,6-naphthalenedicarboxylic acid; diphenyl
ether-4,4'-dicarboxylic acid; 1,6-naphthalenedicarboxylic acid;
2,7-naphthalenedicarboxylic acid; 4,4'-dicarboxybiphenyl;
bis(4-carboxyphenyl)ether; bis(4-carboxyphenyl)butane;
bis(4-carboxyphenyl)ethane; bis(3-carboxyphenyl)ether;
bis(3-carboxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryl
and halogen substituents thereof. Examples of suitable aromatic
diols include hydroquinone; resorcinol; 2,6-dihydroxynaphthalene;
2,7-dihydroxynaphthalene; 1,6-dihydroxynaphthalene;
4,4'-dihydroxybiphenyl; 3,3'-dihydroxybiphenyl;
3,4'-dihydroxybiphenyl; 4,4'-dihydroxybiphenyl ether;
bis(4-hydroxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryl
and halogen substituents thereof. In one particular embodiment, the
aromatic polyester contains monomer repeat units derived from
4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid. The monomer
units derived from 4-hydroxybenzoic acid may constitute from about
45% to about 85% (e.g., 73%) of the polymer on a mole basis and the
monomer units derived from 2,6-hydroxynaphthoic acid may constitute
from about 15% to about 55% (e.g., 27%) of the polymer on a mole
basis. Such aromatic polyesters are commercially available from
Ticona, LLC under the trade designation VECTRA.RTM. A. The
synthesis and structure of these and other aromatic polyesters may
be described in more detail in U.S. Pat. Nos. 4,161,470; 4,473,682;
4,522,974; 4,375,530; 4,318,841; 4,256,624; 4,219,461; 4,083,829;
4,184,996; 4,279,803; 4,337,190; 4,355,134; 4,429,105; 4,393,191;
4,421,908; 4,434,262; and 5,541,240.
Liquid crystalline polyesteramides may likewise be obtained by
polymerizing (1) at least one aromatic hydroxycarboxylic acid and
at least one aromatic aminocarboxylic acid; (2) at least one
aromatic hydroxycarboxylic acid, at least one aromatic dicarboxylic
acid, and at least one aromatic amine and/or diamine optionally
having phenolic hydroxy groups; and (3) at least one aromatic
dicarboxylic acid and at least one aromatic amine and/or diamine
optionally having phenolic hydroxy groups. Suitable aromatic amines
and diamines may include, for instance, 3-aminophenol;
4-aminophenol; 1,4-phenylenediamine; 1,3-phenylenediamine, etc., as
well as alkyl, alkoxy, aryl and halogen substituents thereof. In
one particular embodiment, the aromatic polyesteramide contains
monomer units derived from 2,6-hydroxynaphthoic acid, terephthalic
acid, and 4-aminophenol. The monomer units derived from
2,6-hydroxynaphthoic acid may constitute from about 35% to about
85% of the polymer on a mole basis (e.g., 60%), the monomer units
derived from terephthalic acid may constitute from about 5% to
about 50% (e.g., 20%) of the polymer on a mole basis, and the
monomer units derived from 4-aminophenol may constitute from about
5% to about 50% (e.g., 20%) of the polymer on a mole basis. Such
aromatic polyesters are commercially available from Ticona, LLC
under the trade designation VECTRA.RTM. B. In another embodiment,
the aromatic polyesteramide contains monomer units derived from
2,6-hydroxynaphthoic acid, and 4-hydroxybenzoic acid, and
4-aminophenol, as well as other optional monomers (e.g.,
4,4'-dihydroxybiphenyl and/or terephthalic acid). The synthesis and
structure of these and other aromatic poly(esteramides) may be
described in more detail in U.S. Pat. Nos. 4,339,375; 4,355,132;
4,351,917; 4,330,457; 4,351,918; and 5,204,443.
Regardless of its particular constituents, a melt polymerized
prepolymer may be prepared by introducing the appropriate
monomer(s) (e.g., aromatic hydroxycarboxylic acid, aromatic
dicarboxylic acid, aromatic dial, aromatic amine, aromatic diamine,
etc.) into a reactor vessel to initiate a polycondensation
reaction. The particular conditions and steps employed in such
reactions are well known, and may be described in more detail in
U.S. Pat. No. 4,161,470 to Calundann; U.S. Pat. No. 5,616,680 to
Linstid, III, et al.; U.S. Pat. No. 6,114,492 to Linstid, III, et
al.; U.S. Pat. No. 6,514,611 to Shepherd, et al.; and WO
2004/058851 to Waggoner, which are incorporated herein in their
entirety by reference thereto for all relevant purposes. The vessel
employed for the reaction is not especially limited, although it is
typically desired to employ one that is commonly used in reactions
of high viscosity fluids. Examples of such a reaction vessel may
include a stirring tank-type apparatus that has an agitator with a
variably-shaped stirring blade, such as an anchor type, multistage
type, spiral-ribbon type, screw shaft type, etc., or a modified
shape thereof. Further examples of such a reaction vessel may
include a mixing apparatus commonly used in resin kneading, such as
a kneader, a roll mill, a Banbury mixer, etc.
If desired, the reaction may proceed through the acetylation of the
monomers as referenced above and known the art. This may be
accomplished by adding an acetylating agent (e.g., acetic
anhydride) to the monomers. Acetylation is generally initiated at
temperatures of about 90.degree. C. During the initial stage of the
acetylation, reflux may be employed to maintain vapor phase
temperature below the point at which acetic acid byproduct and
anhydride begin to distill. Temperatures during acetylation
typically range from between 90.degree. C. to 150.degree. C., and
in some embodiments, from about 110.degree. C. to about 150.degree.
C. If reflux is used, the vapor phase temperature typically exceeds
the boiling point of acetic acid, but remains low enough to retain
residual acetic anhydride. For example, acetic anhydride vaporizes
at temperatures of about 140.degree. C. Thus, providing the reactor
with a vapor phase reflux at a temperature of from about
110.degree. C. to about 130.degree. C. is particularly desirable.
To ensure substantially complete reaction, an excess amount of
acetic anhydride may be employed. The amount of excess anhydride
will vary depending upon the particular acetylation conditions
employed, including the presence or absence of reflux. The use of
an excess of from about 1 to about 10 mole percent of acetic
anhydride, based on the total moles of reactant hydroxyl groups
present is not uncommon.
Acetylation may occur in in a separate reactor vessel, or it may
occur in situ within the polymerization reactor vessel. When
separate reactor vessels are employed, one or more of the monomers
may be introduced to the acetylation reactor and subsequently
transferred to the polymerization reactor. Likewise, one or more of
the monomers may also be directly introduced to the reactor vessel
without undergoing pre-acetylation.
The aromatic amide oligomer of the present invention is typically
added to the polymerization apparatus employed during melt
polymerization. Although it may be introduced at any time, it is
normally desired to apply the oligomer before melt polymerization
has been initiated, and typically in conjunction with the precursor
monomers for the liquid crystalline polymer. The relative amount of
the aromatic amide oligomer added to the reaction mixture may be
selected to help achieve a balance between viscosity and mechanical
properties. In most embodiments, for example, the aromatic amide
oligomer is employed in an amount of from about 0.1 to about 5
parts, in some embodiments from about 0.2 to about 4 parts, and in
some embodiments, from about 0.3 to about 1.5 parts by weight
relative to 100 parts by weight of the reaction mixture. The
aromatic amide oligomers may, for example, constitute from about
0.1 wt. % to about 5 wt. %, in some embodiments from about 0.2 wt.
% to about 4 wt. %, and in some embodiments, from about 0.3 wt. %
to about 1.5 wt. % of the reaction mixture. Liquid crystalline
polymers may likewise constitute from about 95 wt. % to about 99.9
wt. %, in some embodiments from about 96 wt. % to about 98.8 wt. %,
and in some embodiments, from about 98.5 wt. % to about 99.7 wt. %
of the reaction mixture. While referred to in terms of the reaction
mixture, it should also be understood that the ratios and weight
percentages may also be applicable to the final polymer
composition. That is, the parts by weight of the oligomer relative
to 100 parts by weight of liquid crystalline polymer and the
percentage of the oligomer in the final polymer composition may be
within the ranges noted above.
In addition to the monomers, oligomer, and optional acetylating
agents, other components may also be included within the reaction
mixture to help facilitate polymerization. For instance, a catalyst
may be optionally employed, such as metal salt catalysts (e.g.,
magnesium acetate, tin(I) acetate, tetrabutyl titanate, lead
acetate, sodium acetate, potassium acetate, etc.) and organic
compound catalysts (e.g., N-methylimidazole). Such catalysts are
typically used in amounts of from about 50 to about 500 parts per
million based on the total weight of the recurring unit precursors.
When separate reactors are employed, it is typically desired to
apply the catalyst to the acetylation reactor rather than the
polymerization reactor, although this is by no means a
requirement.
The reaction mixture is generally heated to an elevated temperature
within the polymerization reactor vessel to initiate melt
polycondensation of the reactants. Polycondensation may occur, for
instance, within a temperature range of from about 210.degree. C.
to about 400.degree. C., and in some embodiments, from about
250.degree. C. to about 350.degree. C. For instance, one suitable
technique for forming an aromatic polyester may include charging
precursor monomers (e.g., 4-hydroxybenzoic acid and
2,6-hydroxynaphthoic acid), aromatic amide oligomer, and acetic
anhydride into the reactor, heating the mixture to a temperature of
from about 90.degree. C. to about 150.degree. C. to acetylize a
hydroxyl group of the monomers (e.g., forming acetoxy), and then
increasing the temperature to a temperature of from about
210.degree. C. to about 400.degree. C. to carry out melt
polycondensation. As the final polymerization temperatures are
approached, volatile byproducts of the reaction (e.g., acetic acid)
may also be removed so that the desired molecular weight may be
readily achieved. The reaction mixture is generally subjected to
agitation during polymerization to ensure good heat and mass
transfer, and in turn, good material homogeneity. The rotational
velocity of the agitator may vary during the course of the
reaction, but typically ranges from about 10 to about 100
revolutions per minute ("rpm"), and in some embodiments, from about
20 to about 80 rpm. To build molecular weight in the melt, the
polymerization reaction may also be conducted under vacuum, the
application of which facilitates the removal of volatiles formed
during the final stages of polycondensation. The vacuum may be
created by the application of a suctional pressure, such as within
the range of from about 5 to about 30 pounds per square inch
("psi"), and in some embodiments, from about 10 to about 20
psi.
Following melt polymerization, the molten polymer may be discharged
from the reactor, typically through an extrusion orifice fitted
with a die of desired configuration, cooled, and collected.
Commonly, the melt is discharged through a perforated die to form
strands that are taken up in a water bath, pelletized and dried.
The resin may also be in the form of a strand, granule, or
powder.
After melt polymerization, the resulting prepolymer is then
subjected to a solid-state polymerization process as is known in
the art. For instance, solid-state polymerization may be conducted
in the presence of a gas (e.g., air, inert gas, etc.). Suitable
inert gases may include, for instance, include nitrogen, helium,
argon, neon, krypton, xenon, etc., as well as combinations thereof.
The solid-state polymerization zone can be of virtually any design
that will allow the polymer to be maintained at the desired
solid-state polymerization temperature for the desired residence
time. Examples of such solid-state polymerization zones can be
reactors that have a fixed bed, static bed, moving bed, etc. The
temperature at which solid-state polymerization is performed may
vary, but is typically within a range of about 200.degree. C. to
about 350.degree. C., in some embodiments from about 225.degree. C.
to about 325.degree. C., and in some embodiments, from about
250.degree. C. to about 300.degree. C. The polymerization time will
of course vary based on the temperature and target molecular
weight. In most cases, however, the solid-state polymerization time
will be from about 2 to about 12 hours, and in some embodiments,
from about 4 to about 10 hours.
Regardless of the particular manner in which it is formed, the
resulting solid-state polymerized liquid crystalline polymer will
generally have a high number average molecular weight (M.sub.n),
such as about 2,000 grams per mole or more, in some embodiments
from about 4,000 grams per mole or more, and in some embodiments,
from about 5,000 to about 30,000 grams per mole. Of course, it is
also possible to form polymers having a lower molecular weight,
such as less than about 2,000 grams per mole, using the method of
the present invention. The intrinsic viscosity of the polymer
composition, which is generally proportional to molecular weight,
may also be relatively high. For example, the intrinsic viscosity
may be about 4 deciliters per gram ("dL/g") or more, in some
embodiments about 5 dL/g or more, in some embodiments from about 6
to about 20 dL/g, and in some embodiments from about 7 to about 15
dL/g. Intrinsic viscosity may be determined in accordance with
ISO-1628-5 using a 50/50 (v/v) mixture of pentafluorophenol and
hexafluoroisopropanol, as described in more detail below.
The melting point of the polymer composition may also range from
about 250.degree. C. to about 400.degree. C., in some embodiments
from about 270.degree. C. to about 380.degree. C., and in some
embodiments, from about 300.degree. C. to about 360.degree. C.
Likewise, the crystallization temperature may range from about
200.degree. C. to about 400.degree. C., in some embodiments from
about 250.degree. C. to about 350.degree. C., and in some
embodiments, from about 280.degree. C. to about 320.degree. C. The
melting and crystallization temperatures may be determined as is
well known in the art using differential scanning calorimetry
("DSC"), such as determined by ISO Test No. 11357.
If desired, the resulting polymer composition may also be combined
with a wide variety of other types of components to form a filled
composition. For example, a filler material may be incorporated
with the polymer composition to enhance strength. A filled
composition can include a filler material such as a fibrous filler
and/or a mineral filler and optionally one or more additional
additives as are generally known in the art.
Mineral fillers may, for instance, be employed in the polymer
composition to help achieve the desired mechanical properties
and/or appearance. When employed, mineral fillers typically
constitute from about 5 wt. % to about 60 wt. %, in same
embodiments from about 10 wt. % to about 55 wt. %, and in some
embodiments, from about 20 wt. % to about 50 wt. % of the polymer
composition. Clay minerals may be particularly suitable for use in
the present invention. Examples of such clay minerals include, for
instance, talc (Mg.sub.3Si.sub.4O.sub.10(OH).sub.2), halloysite
(Al.sub.2Si.sub.2O.sub.5(OH).sub.4), kaolinite
(Al.sub.2Si.sub.2O.sub.5(OH).sub.4), illite
((K,H.sub.3O)(Al,Mg,Fe).sub.2
(Si,Al).sub.4O.sub.10[(OH).sub.2,(H.sub.2O)]), montmorillonite
(Na,Ca).sub.0.33(Al,Mg).sub.2Si.sub.4O.sub.10(OH).sub.2.nH.sub.2O),
vermiculite ((MgFe,Al).sub.3(Al,Si).sub.4O.sub.10(OH).sub.2.
4H.sub.2O), palygorskite
((Mg,Al).sub.2Si.sub.4O.sub.10(OH).4(H.sub.2O)), pyrophyllite
(Al.sub.2Si.sub.4O.sub.10(OH).sub.2), etc., as well as combinations
thereof. In lieu of, or in addition to, clay minerals, still other
mineral fillers may also be employed. For example, other suitable
silicate fillers may also be employed, such as calcium silicate,
aluminum silicate, mica, diatomaceous earth, wollastonite, and so
forth. Mica, for instance, may be particularly suitable. There are
several chemically distinct mica species with considerable variance
in geologic occurrence, but all have essentially the same crystal
structure. As used herein, the term "mica" is meant to generically
include any of these species, such as muscovite
(KAl.sub.2(AlSi.sub.3)O.sub.10(OH).sub.2), biotite
(K(Mg,Fe).sub.3(AlSi.sub.3)O.sub.10(OH).sub.2), phlogopite
(KMg.sub.3(AlSi.sub.3)O.sub.10(OH).sub.2), lepidolite
(K(Li,Al).sub.2-3(AlSi.sub.3)O.sub.10(OH).sub.2), glauconite
(K,Na)(Al,Mg,Fe).sub.2(Si,Al).sub.4O.sub.10(OH).sub.2), etc., as
well as combinations thereof.
Fibers may also be employed as a filler material to further improve
the mechanical properties. Such fibers generally have a high degree
of tensile strength relative to their mass. For example, the
ultimate tensile strength of the fibers (determined in accordance
with ASTM 02101) is typically from about 1,000 to about 15,000
Megapascals ("MPa"), in some embodiments from about 2,000 MPa to
about 10,000 MPa, and in some embodiments, from about 3,000 MPa to
about 6,000 MPa. To help maintain an insulative property, which is
often desirable for use in electronic components, the high strength
fibers may be formed from materials that are also generally
insulative in nature, such as glass, ceramics (e.g., alumina or
silica), aramids (e.g., Kevlar.RTM. marketed by E. I. duPont de
Nemours, Wilmington, Del.), polyolefins, polyesters, etc., as well
as mixtures thereof. Glass fibers are particularly suitable, such
as E-glass, A-glass, C-glass, D-glass, AR-glass, R-glass, S1-glass,
S2-glass, etc., and mixtures thereof.
The volume average length of the fibers may be from about 50 to
about 400 micrometers, in some embodiments from about 80 to about
250 micrometers, in some embodiments from about 100 to about 200
micrometers, and in some embodiments, from about 110 to about 180
micrometers. The fibers may also have a narrow length distribution.
That is, at least about 70% by volume of the fibers, in some
embodiments at least about 80% by volume of the fibers, and in some
embodiments, at least about 90% by volume of the fibers have a
length within the range of from about 50 to about 400 micrometers,
in some embodiments from about 80 to about 250 micrometers, in some
embodiments from about 100 to about 200 micrometers, and in some
embodiments, from about 110 to about 180 micrometers. The fibers
may also have a relatively high aspect ratio (average length
divided by nominal diameter) to help improve the mechanical
properties of the resulting polymer composition. For example, the
fibers may have an aspect ratio of from about 2 to about 50, in
some embodiments from about 4 to about 40, and in some embodiments,
from about 5 to about 20 are particularly beneficial. The fibers
may, for example, have a nominal diameter of about 10 to about 35
micrometers, and in some embodiments, from about 15 to about 30
micrometers.
The relative amount of the fibers in the filled polymer composition
may also be selectively controlled to help achieve the desired
mechanical properties without adversely impacting other properties
of the composition, such as its flowability. For example, the
fibers may constitute from about 2 wt. % to about 40 wt. %, in some
embodiments from about 5 wt. % to about 35 wt. %, and in some
embodiments, from about 6 wt. % to about 30 wt. % of the filled
polymer composition. Although the fibers may be employed within the
ranges noted above, small fiber contents may be employed while
still achieving the desired mechanical properties. For example, the
fibers can be employed in small amounts such as from about 2 wt. %
to about 20 wt. %, in some embodiments, from about 5 wt. % to about
16 wt. %, and in some embodiments, from about 6 wt. % to about 12
wt %.
Still other additives that can be included in the composition may
include, for instance, antimicrobials, pigments (e.g., carbon
black), antioxidants, stabilizers, surfactants, waxes, solid
solvents, and other materials added to enhance properties and
processability. Lubricants, for instance, may be employed in the
polymer composition. Examples of such lubricants include fatty
acids esters, the salts thereof, esters, fatty acid amides, organic
phosphate esters, and hydrocarbon waxes of the type commonly used
as lubricants in the processing of engineering plastic materials,
including mixtures thereof. Suitable fatty acids typically have a
backbone carbon chain of from about 12 to about 60 carbon atoms,
such as myristic acid, palmitic acid, stearic acid, arachic acid,
montanic acid, octadecinic acid, parinric acid, and so forth.
Suitable esters include fatty acid esters, fatty alcohol esters,
wax esters, glycerol esters, glycol esters and complex esters.
Fatty acid amides include fatty primary amides, fatty secondary
amides, methylene and ethylene bisamides and alkanolamides such as,
for example, palmitic acid amide, stearic acid amide, oleic acid
amide, N,N'-ethylenebisstearamide and so forth. Also suitable are
the metal salts of fatty acids such as calcium stearate, zinc
stearate, magnesium stearate, and so forth; hydrocarbon waxes,
including paraffin waxes, polyolefin and oxidized polyolefin waxes,
and microcrystalline waxes. Particularly suitable lubricants are
acids, salts, or amides of stearic acid, such as pentaerythritol
tetrastearate, calcium stearate, or N,N'-ethylenebisstearamide.
When employed, the lubricant(s) typically constitute from about
0.05 wt. % to about 1.5 wt. %, and in some embodiments, from about
0.1 wt. % to about 0.5 wt. % (by weight) of the polymer
composition.
The solid-state polymerized polymer composition of the present
invention may be employed in a wide variety of applications as is
known in the art, such as blow molding, injection molding,
rotational molding, sheet extrusion, thermoforming, etc. Due to its
relatively high "low shear" viscosity and associated high degree of
melt strength, the composition is particularly well suited for
applications that involve the formation of a thin, sheet-like
material or film. In certain embodiments, for example, the
composition may be formed into a film and then "thermoformed" into
the desired shape and/or size of the final product. The film may be
prepared using any known technique, such as with a tubular trapped
bubble film process, flat or tube cast film process, slit die flat
cast film process, etc. Regardless of the manner in which it is
formed, the film may be "thermoformed" by heating the film to a
certain temperature so that it becomes flowable, shaping the film
within a mold, and then trimming the shaped film to create the
desired product. The product may, for example, be a package,
container, tray (e.g., for a food product), electrical connector,
circuit, bottle, pouch, cup, tub, pail, jar, box, etc.
According to one embodiment, a this, sheet-like material of the
composition may be thermoformed by heating it to a certain
temperature so that it becomes flowable, shaping the substrate
within a mold, and then optionally trimming the shaped article to
create the desired article. For example, a polymeric sheet can be
first fed to a heating device that heats it to a temperature
sufficient to cause the polymer to deform or stretch. In general,
any suitable heating device may be used, such as a convection oven,
electrical resistance heater, infrared heater, etc. Once heated,
the polymeric sheet is fed to a molding device where it is molded
into an article. Any of a variety of molding devices may be
employed in the thermoforming process, such as a vacuum mold.
Regardless, a force (e.g., suction force) is typically placed
against the sheet to cause it to conform to the contours of the
mold. At the contours, for instance, the draw ratio may be greater
than 1:1 to about 5:1, Molding of the polymeric sheet typically
occurs before the sheet substantially solidifies and/or
crystallizes. Thus, the properties of the polymer are not only
important during production of the polymeric sheets, but are also
important during the subsequent molding process. If the polymeric
sheet were to solidify and/or crystallize too quickly, the polymer
may tear, rupture, blister or otherwise form defects in the final
article during molding.
Although any suitable three-dimensional article can be formed, a
melt-extruded substrate of composition is particularly well suited
to producing cooking articles, such as cookware and bakeware. For
example, when formed in accordance with the present invention, such
articles can be capable of withstanding very high temperatures,
including any oven environment for food processing. The articles
are also chemical resistant and exceptionally inert. The articles,
for instance, may be being exposed to any one of numerous chemicals
used to prepare foods and for cleaning without degrading while
remaining resistant to stress cracking. In addition, the articles
may also possess excellent anti-stick or release properties. Thus,
when molded into a cooking article, no separate coatings may be
needed to prevent the article from sticking to food items. In this
manner, many bakery goods can be prepared in cookware or bakeware
without having to grease the pans before baking, thus affording a
more sanitary working environment. The substrate also greatly
reduces or eliminates a common issue of trapped food or grease in
corners of rolled metal pans as solid radius corners can be easily
incorporated into cookware.
The present invention may be better understood with reference to
the following examples.
Test Methods
Melt Viscosity: The melt viscosity (Pa-s) was determined in
accordance with ISO Test No. 11443 at 375.degree. C. and at a shear
rate of 400 s.sup.-1 and 1000 s.sup.-1 using a Dynisco 7001
capillary rheometer. The rheometer orifice (die) had a diameter of
1 mm, length of 20 mm, LID ratio of 20.1, and an entrance angle of
180.degree.. The diameter of the barrel was 9.55 mm.+-.0.005 mm and
the length of the rod was 233.4 mm.
Complex viscosity: The complex viscosity is used herein as an
estimate for the "low shear" viscosity of the polymer composition
at low frequencies. Complex viscosity is a frequency-dependent
viscosity, determined during forced harmonic oscillation of shear
stress at angular frequencies of 0.15 and 500 radians per second.
Measurements were determined at a constant temperature of
375.degree. C. and at a constant strain amplitude of 1% using an
ARES-G2 rheometer (TA Instruments) with a parallel plate
configuration (25 mm plate diameter).
Intrinsic Viscosity: The intrinsic viscosity ("IV") may be measured
in accordance with ISO-1628-5 using a 50/50 (v/v) mixture of
pentafluorophenol and hexafluoroisopropanol. Each sample was
prepared in duplicate by weighing about 0.02 grams into a 22 mL
vial. 10 mL of pentafluorophenol ("PFP") was added to each vial and
the solvent. The vials were placed in a heating block set to
80.degree. C. overnight. The following day 10 mL of
hexafluoroisopropanol ("HFIP") was added to each vial. The final
polymer concentration of each sample was about 0.1%. The samples
were allowed to cool to room temperature and analyzed using a
PolyVisc automatic viscometer.
Melting and Crystallization Temperatures: The melting temperature
("Tm") and crystallization temperature ("Tc") were determined by
differential scanning calorimetry ("DSC") as is known in the art.
The melting temperature is the differential scanning calorimetry
(DSC) peak melt temperature as determined by ISO Test No. 11357.
The crystallization temperature is determined from the cooling
exotherm in the cooling cycle. Under the DSC procedure, samples
were heated and cooled at 20.degree. C. per minute as stated in ISO
Standard 10350 using DSC measurements conducted on a TA Q2000
Instrument.
Synthesis of
N4-phenyl-N1-[4-[[4-(phenylcarbamoyl)benzoyl]amino]phenyl]terephthalamide
Compound A
The synthesis of Compound A from 4-amino benzanilide and
terephthaloyl chloride, can be performed according to the following
scheme:
##STR00020##
The experimental setup consisted of a 1 L glass beaker equipped
with a glass rod stirrer coupled with an overhead mechanical
stirrer. 4-aminobenzanilide (20.9 g) was dissolved in warm DMAc
(250 mL) (alternatively N-methylpyrrolidone can also be used).
Terephthaloyl chloride (10 g) was added to the stirred solution of
the diamine maintained at 40-50.degree. C., upon the addition of
the acid chloride the reaction temperature increased from
50.degree. C. to 80.degree. C. After the addition of the acid
chloride was completed, the reaction mixture was warmed to
70-80.degree. C. and maintained at that temperature for about three
hours and allowed to rest overnight at room temperature. The
product was then isolated by the addition of water (500 mL)
followed by vacuum filtration followed by washing with hot water (1
L). The product was then dried in a vacuum oven at 150.degree. C.
for about 6-8 hours, to give a pale yellow colored solid (yield ca.
90%). The melting point by DSC was 462.degree. C.
Synthesis of
N1,N3-bis(4-benzamidophenyl)benzene-1,3-dicarboxamide
Compound C2
The synthesis of Compound C2 from 1,4-phenylene diamine,
terephthaloyl chloride, and benzoyl chloride may be performed
according to the following scheme:
##STR00021##
The experimental setup consisted of a 500 mL glass beaker equipped
with a magnetic stirrer. 1,4 phenylene diamine (20 g) was dissolved
in warm NMP (200 mL) at 40.degree. C. Benzoyl chloride (26.51 g)
was added drop wise to a stirred solution of the diamine over a
period of 30 minutes. After the addition of the benzoyl chloride
was completed, the reaction mixture was warmed to 70-80.degree. C.
and then allowed to cool to 50.degree. C. After cooling to the
desired temperature, isophthaloyl chloride (18.39 g) was added in
small portions such that the temperature of the reaction mixture
did not increase above 70.degree. C. The mixture was then stirred
for additional one (1) hour at 70.degree. C., and was allowed to
rest overnight at room temperature. The product was recovered by
addition of water (200 mL) to the reaction mixture, followed by
filtration and washing with hot water (500 mL). The product was
then dried in a vacuum oven at 150.degree. C. for about 6-8 hours
to give a pale yellow colored solid (yield ca. 90%). The melting
point by DSC was 329.degree. C. The Proton NMR characterization for
the compound is also shown in FIG. 1.
Synthesis of
N1,N3-bis(3-benzamidophenyl)benzene-1,3-dicarboxamide
Compound D2
The synthesis of Compound D2 from 1,3-phenylene diamine,
isophthaloyl chloride, and benzoyl chloride may be performed
according to the following scheme:
##STR00022##
The experimental setup consisted of a 500 mL glass beaker equipped
with a magnetic stirrer. 1,3 phenylene diamine (20 g) was dissolved
in warm DMAc (200 mL) at 40.degree. C. Benzoyl chloride (26.51 g)
was added drop wise to a stirred solution of the diamine over a
period of 30 minutes. After the addition of the benzoyl chloride
was completed, the reaction mixture was warmed to 70-80.degree. C.
and allowed to cool to 50.degree. C. After cooling to the desired
temperature, isophthaloyl chloride (18.39 g) was added in small
portions such that the temperature of the reaction mixture did not
increase above 70.degree. C. The mixture was then stirred for
additional one hour at 70.degree. C., and was allowed to rest
overnight at room temperature. The product was recovered by
addition of water (200 mL) to the reaction mixture, followed by
filtration and washing with hot water (500 mL). The product was
then dried in a vacuum oven at 150.degree. C. for about 6-8 hours
to give a pale yellow colored solid (yield ca. 90%). The Proton NMR
characterization for the compound is also shown in FIG. 2.
Synthesis of N1,N3,N5-triphenylbenzene-1,3,5-tricarboxamide
Compound F
Compound F was synthesized from trimesoyl chloride and aniline
according to the following scheme:
##STR00023##
The experimental set up consisted of a 2 L glass beaker equipped
with a glass rod stirrer coupled with an overhead mechanical
stirrer. Trimesoyl chloride (200 g) was dissolved in dimethyl
acetamide ("DMAc") (1 L) and cooled by an ice bath to 10-20.degree.
C. Aniline (421 g) was added drop wise to a stirred solution of the
acid chloride over a period of 1.5 to 2 hours. After the addition
of the amine was completed, the reaction mixture was stirred
additionally for 45 minutes, after which the temperature was
increased to 90.degree. C. for about 1 hour. The mixture was
allowed to rest overnight at room temperature. The product was
recovered by precipitation through the addition of 1.5 L of
distilled water, which was followed by was vacuum filtration using
a filter paper and a Buchner funnel. The crude product was washed
with acetone (2 L) and then washed again with hot water (2 L). The
product was then air dried over night at room temperature and then
was dried in a vacuum oven 150.degree. C. for 4 to 6 hours. The
product (250 g) was a white solid, and had a melting point of
319.6.degree. C., as determined by differential scanning
calorimetry ("DSC"). The Proton NMR characterization for the
compound is shown in FIG. 3.
Synthesis of
N1,N3,N5-tris(4-benzamidophenyl)benzene-1,3,5-tricarboxamide
Compound H
The synthesis of Compound H from trimesoyl chloride and
4-benzoanilide may be performed according to the following
scheme:
##STR00024##
The experimental setup consisted of a 2 L glass beaker equipped
with a glass rod stirrer coupled with an overhead mechanical
stirrer. Trimesoyl chloride (27.8 g) was dissolved in DMAc (100 mL)
at room temperature. 4-aminobenzanilide (69.3 g) was dissolved in
DMAc (250 mL). The amine solution was gradually added to the acid
chloride solution over a period of fifteen minutes, the reaction
mixture was then stirred and the temperature was increased to
90.degree. C. for about three hours. The mixture was allowed to
rest overnight at room temperature. The product was recovered by
precipitation by addition of 1.5 L of distilled water and followed
by was vacuum filtration using a filter paper and a Buchner funnel.
The crude product was then washed with acetone (500 mL) and then
washed again with hot water (1 L). The product was then air dried
over night at room temperature and then was dried in a vacuum oven
150.degree. C. for 4-6 hours. The product (yield-80-85%) was a
bright yellow solid. The Proton NMR characterization for the
compound is shown in FIG. 4.
Synthesis of
N1,N3,N5-tris(3-benzamidophenyl)benzene-1,3,5-tricarboxamide
Compound I
The synthesis of Compound I from trimesoyl chloride, benzoyl
chloride and 1,3-phenylene diamine can be performed according to
the following scheme:
##STR00025##
The experimental set up consisted of a 1 L glass beaker equipped
with a glass rod stirrer coupled with an overhead mechanical
stirrer. 1,3 phenylene diamine (20 g) was dissolved in warm
dimethyl acetamide (200 mL) (alternatively N-methylpyrrolidone can
also be used) and maintained at 45.degree. C. Next benzoyl chloride
(26.51 g) was slowly added drop wise over a period of 1.5 to 2
hours, to the amine solution with constant stirring. The rate of
addition of the benzoyl chloride was maintained such that the
reaction temperature was maintained less than 60.degree. C. After
complete addition of the benzoyl chloride, the reaction mixture was
gradually warmed to 85-90.degree. C. and then allowed to cool to
around 45-50.degree. C. At this point, trimesoyl chloride (16.03 g)
was gradually added to the reaction mixture such that the exotherm
did not increase the reaction temperature above 60.degree. C. After
complete addition of the trimesoyl chloride, the reaction mixture
was allowed to stir for additional 45 minutes, after which the
reaction temperature was increased to 90.degree. C. for about 30
minutes and then was cooled to room temperature. The mixture was
allowed to rest overnight at room temperature. The product was
recovered by precipitation through the addition of 1.5 L of
distilled water, which was followed by was vacuum filtration using
a filter paper and a Buchner funnel. The crude product was then
washed with acetone (250 mL) and washed again with hot water (500
mL). The product (yield: ca. 90%) was then air dried over night at
room temperature and then was dried in a vacuum oven 150.degree. C.
for 4 to 6 hours. The product was a pale tan solid. The Proton NMR
characterization was as follows: .sup.1H NMR (400 MHz
d.sub.6-DMSO): 10.68 (s, 3H, CONH), 10.3 (s, 3H, CONH), 8.74 (s,
3H, central Ar), 8.1 (d, 3H, m-phenylene Ar), 7.9 (d, 6H,
ortho-ArH), 7.51 (m, 15H, meta-para-ArH and 6H, m-phenylene Ar) and
7.36 (m, 3H, m-phenylene Ar).
Example 1
A 2 L flask was charged with 4-hydroxybenzoic acid (415.7 g),
2,6-hydroxynaphthoic acid (32 g), terephthalic acid (151.2 g),
4,4'-biphenol (122.9 g), acetaminophen (37.8 g), and 50 mg of
potassium acetate. The flask was equipped with C-shaped stirrer, a
thermal couple, a gas inlet, and distillation head. The flask was
placed under a low nitrogen purge and acetic anhydride (99.7%
assay, 497.6 g) was added. The milky-white slurry was agitated at
75 rpm and heated to 140.degree. C. over the course of 95 minutes
using a fluidized sand bath. After this time, the mixture was then
gradually heated to 360.degree. C. steadily over 300 minutes.
Reflux was seen once the reaction exceeded 140.degree. C. and the
overhead temperature increased to approximately 115.degree. C. as
acetic acid byproduct was removed from the system. During the
heating, the mixture grew yellow and slightly more viscous and the
vapor temperature gradually dropped to 90.degree. C. Once the
mixture had reached 360.degree. C., the nitrogen flow was stopped.
The flask was evacuated below 20 psi and the agitation slowed to 30
rpm over the course of 45 minutes. As the time under vacuum
progressed, the mixture grew viscous. After 72 minutes, the final
viscosity target was reached as gauged by the strain on the
agitator motor (torque value of 30 units). The reaction was then
stopped by releasing the vacuum and stopping the heat flow to the
reactor. The flask was cooled and then polymer was recovered as a
solid, dense yellow-brown plug. Sample for analytical testing was
obtained by mechanical size reduction.
Example 2
A melt polymerized prepolymer was formed as described in Example 1,
except that 19.65 grams of Compound A was also introduced into the
reactor. It was observed that there were fewer residues in the
distillate as compared to Example 1. The reaction was stopped after
72 minutes--no torque was observed on the agitator motor.
Example 3
A melt polymerized prepolymer was formed as described in Example 1,
except that 19.76 grams of Compound F was also introduced into the
reactor. It was observed that there were fewer residues in the
distillate as compared to Example 1. The reaction was stopped after
72 minutes--no torque was observed on the agitator motor.
Example 4
A melt polymerized prepolymer was formed as described in Example 1,
except that 18.7 grams of Compound H was also introduced into the
reactor. It was observed that there were fewer residues in the
distillate as compared to Example 1. The reaction was stopped after
72 minutes--a torque value of 50 units was observed on the agitator
motor.
The thermal properties of the melt polymerized prepolymers of
Examples 1-4 were tested as described above. The results are set
forth below in Table 1.
TABLE-US-00002 TABLE 1 Properties of Melt Polymerized Prepolymers
MV at MV at Tm Tc 1000 s.sup.-1 400 s.sup.-1 Example Additive
(.degree. C.) (.degree. C.) IV (dL/g) (Pa * s) (Pa * s) 1 -- 361.6
301.8 8.4 75.7 118.2 2 A 350.6 299.3 5.3 46.8 70.7 3 F 322.4 275.1
3.8 27.7 43.6 4 H 343.0 284.7 5.0 137.8 230.1
Example 5
The melt polymerized prepolymers of Examples 1-4 were solid-state
polymerized by heating the prepolymers in an air circulated oven
for eight (8) hours. The oven was maintained at 280.degree. C. The
polymer flakes (80 g) were placed uniformly in a thin layer within
a glass tray. The thermal and rheological properties of the
"solid-state polymerized" polymers were then tested as described
above. The results are set forth below in Table 2.
TABLE-US-00003 TABLE 2 Properties of Solid-State Polymerized
Compositions Ratio of Ratio of Solid State Solid State MV to MV to
Complex Intrinsic MV at Prepolymer MV at Prepolymer Viscosity Tm Tc
Viscosity 1000 s.sup.-1 MV 400 s.sup.-1 MV (Pa * s), Example
Additive (.degree. C.) (.degree. C.) (dL/g) (Pa * s) (at 1000
s.sup.-1) (Pa * s) (at 400 s.sup.-1) 0.15 rad/s 1 -- 359.8 299.6
12.6 263.2 3.48 561.2 4.75 51,520 2 A 350.6 299.1 8.3 139.6 2.98
259.9 3.67 145,842 3 F 323.1 275.8 6.8 225.0 8.12 455.9 10.46
116,438 4 H 355.5 298.7 8.6 860.0 6.24 3163.8 13.75 801,447
As indicated, the use of Compounds A, F, and H in Examples 2-4
resulted in a significant increase in the complex viscosity at a
frequency of 0.15 rad/s. Other frequencies were also tested, the
results of which are shown in FIG. 5. Furthermore, as evidenced by
the ratio of the solid state MV to the prepolymer MV, Compounds F
and H significantly accelerated the extent to which melt viscosity
was increased during solid-state polymerization. Although the
polymerization time was held constant in these experiments, the
increased rate at which MV was increased (indicative of an
increased rate of prepolymer chain extension) can substantially
reduce the solid-state polymerization time needed to achieve a
certain molecular weight.
These and other modifications and variations of the present
invention may be practiced by those of ordinary skill in the art,
without departing from the spirit and scope of the present
invention. In addition, it should be understood that aspects of the
various embodiments may be interchanged both in whole or in part.
Furthermore, those of ordinary skill in the art will appreciate
that the foregoing description is by way of example only, and is
not intended to limit the invention so further described in such
appended claims.
* * * * *